@inproceedings{a.1956the,
title={The boundary correspondence under quasiconformal mappings},
author={A. Beurling, and L. Ahlfors},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203145266833837},
booktitle={Acta Mathematica},
volume={96},
number={1},
pages={125-142},
year={1956},
}
A. Beurling, and L. Ahlfors. The boundary correspondence under quasiconformal mappings. 1956. Vol. 96. In Acta Mathematica. pp.125-142. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203145266833837.